While smoking causes over 443,000 deaths annually, it remains one of the most heavily marketed products in the Unites States. By far, most of the marketing efforts of the tobacco industry occur at the point-of-sale (POS), i.e., at retail stores where tobacco is sold. There are no empirical studies in the United States on the effect of POS tobacco marketing on smoking cessation. The broad, long-term objective of this proposal is to contribute to the knowledge of how tobacco control policies, e.g., POS marketing regulations, affect smoking behavior and thus to produce the required evidence base that can guide future policies. The specific aim of the proposal is to determine the effect of exposure to POS tobacco marketing on smoking cessation among smokers 18 years of age or older. The central hypothesis is that exposure to higher levels of POS tobacco marketing hinders making a quit attempt and quit success. The mechanism underlying how POS tobacco marketing hinders quit attempt and success also will be examined. In this regard, the proposal hypothesizes that smokers who are exposed to a higher level of POS marketing will more frequently crave to smoke, have an urge to buy cigarettes, and make unplanned purchases of cigarettes, which will lower the chances of making a quit attempt and successfully quitting. It is further hypothesized that smokers who are exposed to higher amounts of POS marketing will have a stronger belief that smoking is socially acceptable and as a result will be less motivated to make a quit attempt and successfully quit smoking. To test these hypotheses and achieve the specific aim of the proposal, a population-based longitudinal study of a cohort of smokers in Omaha, Nebraska will be conducted. The participants will be recruited through random digit dialing of landline telephone and cell phone numbers and interviewed at baseline and a six-month follow-up. At baseline, data on POS tobacco marketing will be collected from stores that sell tobacco in each participant's neighborhood. Also at baseline, data will be collected from each participant about noticing POS marketing, craving to smoke, urge to buy cigarettes, unplanned purchase of cigarettes, and the perception of social acceptability of smoking. At the six-month follow-up, quit attempts in the previous six months and quit success will be assessed. This study is especially important in the wake of the 2009 Family Smoking Prevention and Tobacco Control Act, which authorizes the Food and Drug Administration (FDA) to regulate tobacco marketing and preserves state and local authority to enact tobacco marketing laws. Thus, the study is significant not only because it will fill a gap in our knowledge of how POS tobacco marketing affects smoking cessation, but also because this knowledge can be used by the FDA and state and local jurisdictions to formulate future tobacco marketing regulations.